FISH OIL AND DOGS

Dear Dr. Shawn:”I’ve been using fish oil for my dog and cat for the last 2 years. My dog Annie has allergies and her doctor recommended adding fish oil to help control her itching. My cat Julie doesn’t have any medical problems but the fish oil helps her coat stay shiny and she isn’t as flaky as she used to be in the past. I was wondering if it is safe to continue using the fish oil. Are there any side effects from long term use?”

A:”Fish oil is one of my favorite supplements for a variety of problems in both dogs and cats. As you mentioned, even normal pets can benefit from improved haircoats when supplemented with fatty acids such as fish oil. In people, there is good evidence for DHA/EPA (the 2 main fatty acids in fish oil) lowering triglyceride levels in the blood. There is also good evidence that fish oil can reduce secondary cardiovascular disease (heart attacks, abnormal heart rhythms, etc.) and probably primary disease, decrease blood pressure, and improves rheumatoid arthritis. Research indicates that fish oil may possibly be helpful in preventing stroke, cancer, allergies, and alleviating signs of depression. Large doses of fish oil are typically necessary, usually on the order of 1-3 grams of EPA/DHA per day. In pets, fish oil is useful for reducing inflammation in pets with allergic skin disease and kidney failure. It possibly also helps pets with heart disease and osteoarthritis. Studies show that pets fed high doses of fish oil also have better control of cancer. Extra vitamin E is needed when giving fish oil on a regular basis as fish oil supplemented for many months can lower vitamin E levels (most fish oil supplements contain additional vitamin E for this reason.) Side effects are very rare in people and pets using fish oil. In my practice, a very few number of dogs develop a “fishy” smell. Fish oil may decrease platelet aggregation and prolong bleeding time. Pets taking high doses (3-4 times the label dose or greater) should be monitored for bleeding disorders, although I have not seen this even with these larger doses. There is concern about environmental contamination of fish oil with toxins. Studies have shown that fish meat (not oil) may be contaminated with methylmercury. Finally, in people, there are multiple cases of bleeding when fish oil given at high doses is combined with ginkgo (another blood thinner.) This could also occur in pets. This is a great reason why owners should not indiscriminately supplement their pets without veterinary supervision. From your letter it seems like both of your pets are doing fine and side effects are not expected to occur.

Dr. Shawn Messonnier is the author of the award-winning The Natural Health Bible for Dogs & Cats and the newly released 8 Weeks to a Healthy Dog.

He can be reached at naturalvet@juno.com